Sorry for the link-dump, but what's the chance that we're going to see this diversity in Outerra?
(Also, notice how the wind affects the movement of the foliage in this video!)
Simulating wind could be difficult though, as you'd expect strong drafts in open and/or high areas, and even stronger winds in alley's and such, while in other parts, obstructions can cause circulating winds.
Just as water behaves according to the complex rules of fluid-dynamics, the movement of air could also be a real pain in the *ss to simulate correctly.